interpreting hydrogen breath test . Effect of oral microflora on

increasing dysuria and discomfort and was passing debris. Various organisms including Proteus mirabilis, Candida albicans, Escherichia coli, and Pseudomonas aeruginosa were isolated on different occasions and he received a variety of antibiotics including augmentin, nalidixic acid, and gentamicin. He was finally admitted in November 1985 as an emergency with severe pain. Cystotomy was undertaken and a free-floating mass removed from his bladder. Unfortunately, he made a poor recovery and died two days later; permission for necropsy was refused. The surgical specimen comprised a mass 110 x 70 x 40 mm which was generally pale brown but with some friable white material on the surface. On sectioning, it was found to consist of concentric layers of soft slightly gritty material (fig 2), the appearances being very similar to that of a cut onion. Haematoxylin and eosin stained sections showed the mass to consist of layers of amorphous material, which stained positively with alcian blue and periodic acid Schiff. Occasional areas showed fibrin deposition with MSB stain. Gram positive cocci and yeast-like fungi showing profuse mycelial growth and spore formation in keeping with Candida species were present particularly near the surface. X-ray microanalysis was performed on samples from three areas; this showed the main mineral constituents to be phosphate and calcium which occurred in variable proportions.